This study is a randomized controlled trial to investigate conservative treatments for individuals with painful knee osteoarthritis (OA). The study will recruit participants who have isolated, medial compartment knee OA. Subjects will be assigned to one of two gait training groups. Both groups will undergo gait analysis to determine their foot progression angle at their comfortable walking speed. Both groups will receive personalized gait retraining to either alter their foot progression angle or to achieve consistency of their natural foot progression angle.